001    // Copyright 2007, 2008, 2010 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    // http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry5.internal.services;
016    
017    import java.io.IOException;
018    import java.io.PrintWriter;
019    
020    import org.apache.tapestry5.ContentType;
021    import org.apache.tapestry5.SymbolConstants;
022    import org.apache.tapestry5.internal.InternalConstants;
023    import org.apache.tapestry5.ioc.annotations.Symbol;
024    import org.apache.tapestry5.json.JSONObject;
025    import org.apache.tapestry5.services.ComponentEventResultProcessor;
026    import org.apache.tapestry5.services.Response;
027    
028    /**
029     * Implementation of {@link ComponentEventResultProcessor} for {@link org.apache.tapestry5.json.JSONObject}, allowing a
030     * component event handler to return a JSONObject that will be sent directly to the client as the reply. This is often
031     * used with custom components that need a custom JSON response.
032     */
033    public class JSONObjectEventResultProcessor implements ComponentEventResultProcessor<JSONObject>
034    {
035        private final Response response;
036    
037        private final String outputEncoding;
038    
039        private final boolean compactJSON;
040    
041        public JSONObjectEventResultProcessor(Response response,
042    
043        @Symbol(SymbolConstants.CHARSET)
044        String outputEncoding,
045    
046        @Symbol(SymbolConstants.COMPACT_JSON)
047        boolean compactJSON)
048        {
049            this.response = response;
050            this.outputEncoding = outputEncoding;
051            this.compactJSON = compactJSON;
052        }
053    
054        public void processResultValue(JSONObject value) throws IOException
055        {
056            ContentType contentType = new ContentType(InternalConstants.JSON_MIME_TYPE, outputEncoding);
057    
058            PrintWriter pw = response.getPrintWriter(contentType.toString());
059    
060            value.print(pw, compactJSON);
061    
062            pw.close();
063        }
064    }